Cisco GainMaker Optoelectronic Node 1GHz with 65 86 MHz Split Installation Guide
Reverse Balancing the Node with Digital Reverse Modules
1 Refer to the reverse system design print on the RF amplifier assembly cover and
inject the proper level into the reverse injection (forward output) test point of a
port of the RF launch amplifier with a reverse sweep transmitter or a CW signal
generator. The insertion loss of all forward output test points is 20 dB (relative to
corresponding port).
Note: For the location of the reverse injection test point of each port, see
Note: For the location of the reverse injection test point of each port, see
Illustrations.
Important: To calculate the correct signal level to inject, add the reverse input
Important: To calculate the correct signal level to inject, add the reverse input
level (from the design print) to the insertion loss of the reverse injection test
point.
Formula:
Reverse input + Insertion loss = Signal generator setting
Example:
Reverse input = 17 dBmV
Insertion loss = 20 dBmV
Result: Signal generator setting=17 dBmV + 20 dB = 37 dBmV
Note: The ADC full-scale (100%) level for a single CW carrier is +33 dBmV. This
Formula:
Reverse input + Insertion loss = Signal generator setting
Example:
Reverse input = 17 dBmV
Insertion loss = 20 dBmV
Result: Signal generator setting=17 dBmV + 20 dB = 37 dBmV
Note: The ADC full-scale (100%) level for a single CW carrier is +33 dBmV. This
is the level at which the ADC begins clipping.
Note: The reverse attenuator (pad) and reverse equalizer in the GainMaker Node
Note: The reverse attenuator (pad) and reverse equalizer in the GainMaker Node
is selected during the reverse system design, and it is based on the drive level
into the digital module which is determined by system performance
requirements, type and quantity of return carriers, etc. Consult data sheet to
determine proper operational level.
2 Verify the level of the reverse output test point. This output level leaves the RF
launch amplifier via the coaxial cable to the multiplexing digital module input.
(Use an SMB connector to F-connector test cable.)
3 Have the person in the headend refer to the headend system design and set the
output of the bdr receiver to the specified output level. See the instruction guide
that was shipped with bdr receiver for setup procedures.
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